Among the following, the correct statement(s) about polymers is(are) (A) The polymerization of chloroprene gives natural rubber. (B) Teflon is prepared from tetrafluoroethene by heating it with persulphate catalyst at high pressures. (C) PVC are thermoplastic polymers. (D) Ethene at 350 - 570 K temperature and 1000-2000 atm pressure in the presence of a peroxide initiator yields high density polythene.